The invention relates to a device for reading charges of several light-sensitive or X-ray sensitive sensor elements which are arranged in rows and columns in a matrix, each sensor element comprising a respective electric switch, for each sensor column there being provided a common read line while for each sensor row there is provided a switching line via which the switches of the sensors can be activated so that the charges of the sensor elements of the activated row are output via the read lines.
A device of this kind is known, for example from DE-OS 35 31 448 which corresponds to U.S. Pat. No. 4,689,487. The cited document describes a matrix of photocells for an X-ray imaging apparatus, the charges of the photocells being read in that the switches associated with each sensor are activated via a switching line provided per row. The reading of the charges stored in the sensor is column-wise performed via a respective common read line. In devices of this kind a problem is encountered in that the parasitic capacitances of the read lines and the switches, via which the charge of each sensor element is read, have an adverse effect on the signal read.